Periodontal Bony Defects Research Articles

Bone Apposition in Surgical Bony Defects Following Orthodontic Movement: A Comparative Histomorphometric Study Between Root‐ and Periodontal Ligament‐Damaged and Periodontally Intact Rat Molars

The influence of orthodontic tooth movement with diminished periodontal support is unclear. The aim of the present study was to evaluate bone healing in surgical defects following orthodontic tooth movement with and without periodontal ligament (PDL) and root surface damage. The study comprised 33 adult male Wistar rats, divided into two groups: group 1 (n = 14) with bony defect and no root damage and group 2 (n = 19) with periodontal bony defect including root/PDL damage on the mesial root of the maxillary first molar. One week after a surgical defect was created, orthodontic protraction of the right maxillary first molar was initiated in both groups. After 2 weeks of protraction, retention of 1 week was established; at the end of this period block sections were made. Histomorphometric analysis through light microscopy of decalcified tissue was performed. Results were statistically analyzed using independent samples t test and analysis of variance (ANOVA) with repeated measures. Differences between groups in total area of bone defect and bone apposition were not statistically significant. Bone apposition calculated as percentage of the bone defect was significantly (t-test) greater (P = 0.002) in group 2 (46.21%) than in group 1 (24.95%). Within each group, area of bone apposition was significantly (ANOVA) greater in the distal than in the mesial quadrants of the bony defect (P = 0.006) and in the apical than the occlusal ones (P = 0.021). Following orthodontic tooth movement, periodontal bony defects showed enhanced bony healing compared with alveolar bone defects with no direct association with the periodontal attachment apparatus.

Inflammatory cell population and bacterial contamination of membranes used for guided tissue regenerative procedures.

The purpose of this study was to determine the types of inflammatory cells and bacterial contamination on expanded polytetrafluoroethylene (ePTFE) membranes which might affect new tissue formed by guided tissue regeneration (GTR). Forty periodontal bony defects were treated by the flap procedure, which included the use of an ePTFE membrane. Twelve months after the second surgery, the defect sites were re-evaluated for changes in probing depth and clinical attachment level. The ePTFE membranes were retrieved after 4 to 6 weeks of healing and sectioned serially at 3 microm in a coronal-apical plane. The ePTFE membrane was divided into 3 portions: cervical, middle, and apical, each of which was subdivided into outer, central, and inner segments, providing a total of 9 fields. Cells and bacteria were analyzed by light microscopy for their types: mononuclear cell, erythrocyte, fibroblast, neutrophil, plasma cell, T lymphocyte, B lymphocyte, macrophage, and oral bacteria. Both cells and bacteria decreased in number towards the apical portion and were present even in the central part. Most cells were mononuclear cells. Erythrocytes, fibroblasts, neutrophils, and plasma cells were rarely encountered. Bacteria, most of which were Gram-positive, were observed in almost the same number in the outer and inner parts. The results indicate that numerous inflammatory cells adhered to and invaded the ePTFE membranes accompanied by bacterial contamination and that there was a tendency for a negative correlation between the increment number of bacteria and the gain of clinical attachment level.

Antigenicity of Freeze‐Dried Cortical Bone Allograft in Human Periodontal Osseous Defects

The purpose of this investigation was to determine whether donor-specific anti-HLA antibodies could be detected against freeze-dried cortical bone allograft (FDBA) placed in human periodontal osseous defects. Twenty patients with multiple periodontal bony defects amenable to treatment in two allografting procedures were enrolled. No patient had pre-existing anti-HLA antibodies. FDBA used for all allografting procedures was obtained from one donor of known HLA antigens, and all patients were tissue-typed. Serum samples were taken two weeks after the first allograft (primary challenge), two weeks after the second allograft (secondary challenge) and at three months. Serum samples were assayed for the presence of anti-HLA antibodies using an Amos modified microcytotoxicity assay. At no time could any donor-specific anti-HLA antibodies be detected in any patient. All allografts were judged clinically successful, with no adverse tissue reactions to the donor material. FDBA may be regarded as a graft material lacking clinically significant antigenicity.

Repair of periodontal angular bony defects evaluated by one- and two-dimensional radiographic analysis

The healing of eighteen angular periodontal bony defects was evaluated radiographically 1 year after treatment. The pretreatment and posttreatment radiographs were exposed and processed in such a way that identical images were obtained. There was no correlation between one- and two-dimensional expressions of healing in such defects, and relative area changes were consistently larger than relative linear changes of the same defects. The area gain of bone was strongly correlated to the following morphologic variables: length of bone surface, original defect area, and height of the defect.

Clinical and histological characteristics of lyophilized allogenic dura mater in periodontal bony defects in humans.

This clinical and histological study investigated the use of lyophilized, allogenic dura mater (Lyodura) as a periodontal implant material in interdental bony defects (2-wall lesions) in humans. For 23 defects in 8 subjects a modified Widman flap was raised, curettage performed and the defects bridged with the implant. The same procedure, without Lyodura implantation, was performed on 23 contralateral teeth. By a standardized method, involving the use of a removable stent, the following clinical measurements were recorded after 24 and 48 weeks: the probing attachment level, the probing bone level, the probing pocket depth and the labial and interdental gingival recession. For the histological study 5 additional, interdental craters and 5 control defects were treated as in the clinical study. They were block-sectioned after 1, 2, 6, 12 and 24 weeks and processed in the usual manner for routine examination by light and polarization microscopy. From the clinical study it could be concluded that, in absolute values, only the experimental side showed a significant gain in probing attachment level and a greater reduction of the probing pocket depth. In percentage values the labial gingival recession was significantly lower and the bone formation significantly more pronounced on the experimental side. The histological examination showed that the implant remodelled completely without rejection phenomena. It was replaced gradually, after enzymatic breakdown, by the host's own collagen through the action of invading fibroblasts. Bone formation occurred along but never in the implant. The implant material seems to act as a barrier against epithelial downgrowth and infiltration of inflammatory cells.

Bone induction in experimental periodontal bony defects in dogs with decalcified allogeneic bone matrix grafts: A preliminary study

Decalcified allogeneic bone matrix grafts have been studied in periodontal bony defects in twenty-seven dogs. DABM grafts were resorbed and replaced by new bone. There occurred union of new bone to the cemental (tooth) surface (ankylosis). Clinical, radiologic, fluorescent, and histologic studies revealed that such grafts could ultimately be of use in human beings, especially since these grafts are not rejected and, to our knowledge, do not cause any immunologic response.